A Muslim school in the Sussex countryside being searched by more than 100 police officers was first reported to the Government as being a suspected training camp for terrorists more than seven years ago.

Police officers search the 54 acres of grounds surrounding the Jameah Islamiyah school in Mark Cross, East Sussex

Police descended on Jameah Islamiyah at Mark Cross over the weekend and their searches are expected to last days, if not weeks.

Although there is no suggestion that either the owner or his staff knew of any illegal activities going on at the 54-acre site surrounding the dilapidated, former convent, it emerged yesterday that the Yemeni ambassador to London warned the Government in January 1999, that the site was being used to train young Islamic extremists.

The warning came after a group of British Muslims was arrested in Aden over an alleged bomb plot. Robin Cook, then foreign secretary, told the Commons: "There have been investigations into the matter. The training provided purports to be survival training and also martial arts. We have not established that there was any breach of British law during such training."

At the time, Sussex police said that the reports of the school grounds being used as a terrorist training camp appeared "totally unsubstantiated".

It is known that in the late 1990s Abu Hamza, the jailed cleric, held a camp at the school, a charitable institution that currently has only 12 students, aged 11 to 16, in a complex of buildings with almost 100 rooms.

Bilal Patel, who bought the site in 1993 for £800,000 when it was being run as a ballet school, said that he had asked Hamza and his 15 or so followers to leave because their behaviour was "strange". He said that he had received a letter from Hamza which he had handed over to the police because he "did not like" the contents.

"When Hamza arrived we were immediately concerned about his strange behaviour," said Mr Patel, a former imam in south London.

"He and his followers set up camp in the grounds and kept themselves to themselves. We had to tell Abu Hamza that we did not want him to come back again because he was so strange."

According to Sky News yesterday, there were also reports that some of those being held at Guantanamo Bay had receiving training at a camp in the woodland surrounding the school.

Clearly, though, police did not believe they were at any risk when they moved on to the site early on Saturday morning: none was armed and officers conducted their searches in normal uniforms, rather than protective suits.

"We are interested in the people who have visited here," one officer said yesterday. "There has been a lot of speculation about training camps. The radicalisation of would-be recruits is very important to us."

The school offers itself as a retreat for Muslim families and groups, as a training base for Islamic teachers and as a site for camps for Islamic groups.

Parties were frequently seen arriving at the school in coaches from London or by mini-bus from Tunbridge Wells station.

The school received a critical report from Ofsted inspectors just before Christmas. It was criticised for a lack of involvement with the local community or nearby schools, failures in general education and the poor fabric of the buildings.